Blow molded containers have been produced heretofore for wide and various useage. In general, however, the blow molded containers have historically been used for packaging materials for consumer use in one gallon size or less. A lack of large capacity blow molded containers has resulted from a lack of suitable handling means--an inability to manufacture same.
Blow molded containers are produced when a parison of a fluent plastic material is secured in a mold and a blow pin or other means is inserted to propel air under pressure into the inside of the parison, whereby the fluent plastic material of the parison is expanded by the air into conformity with the mold cavities. Once the plastic cools, the shape defined by the cavities is retained and the molded product is produced. Excess plastic material known as flashing is found adjacent the periphery of the mold junctions and is trimmed off automatically or manually to afford the finished unitary container.
Blow molding has provided a capability of production of numerous design variations that were heretofore not feasible with deep draw, injection, or other molding techniques. The use of blow molding is hence quite desirable to enable one to produce a plastic container with a particular shape or configuration without exhorbitant costs. Shape and design could be directed to a hollow handle or some other functional portion of the container or could be directed purely to the aesthetics of the container or a part thereof.
In general, as mentioned above, blow molded containers have been limited as to size from a practical handling standpoint. While large plastic containers, 30 to 50 gallons capacity, for example, were practical based on available machinery and technology, the physical handling of a 30 to 50 gallon container full of a liquid having a similar density to that of water has previously been impractical. Suitable means for manipulating the filled containers during handling were not available. For example, while metal containers have lifting ribs around the girth to receive the tines of a fork lift and be individually handled thereby, such a handling technique for blow molded containers is dangerous due to the pliability of the plastic. The filled container could slip from between the fork lift tines. Likewise, the containers generally are not rigid to the same standard of a metal container whereby it is difficult to pass the tines of a fork lift beneath the container for lifting while balancing the container. Conventional molding techniques dictate the use of radiused corners and edges as opposed to sharply defined corners and edges that may be found on metal containers. The rounded bottom edges of the blow molded containers thus dictate different handling techniques from comparable metal containers.
One or more of the above noted disadvantages found with use of large capacity blow molded containers has generally precluded successful commercialization of same.
The present invention now provides a large capacity container that is capable of being easily handled in a suitable fashion such that the problems of the prior art are obviated. In this regard, the present invention represents an advance in the art, as exemplified by unexpected improvement as will be more particularly defined hereinafter. The prior art is devoid of any teaching or suggestion of the container of the present invention. Exemplary of the prior art are U.S. Pat. No. 2,913,140 to Vuillemenot; U.S. Pat. No. 3,025,947 to Hammer; U.S. Pat. No. 3,180,512 to Moss; U.S. Pat. No. 3,297,350 to Hidding; U.S. Pat. No. 3,308,997 to Kelly; U.S. Pat. No. 3,318,630 to Bryant; U.S. Pat. No. 3,350,132 to Ashton; U.S. Pat. No. 3,369,690 to Hayes; U.S. Pat. No. 3,383,017 to Krings; U.S. Pat. No. 3,581,930 to Gunnink, and U.S. Pat. No. 3,737,069 to Owen.